Yes, but think about the time Rainbow and Pinkie were pranking everypony in "Griffon the Brush-Off".Rainbow still had no second thoughts about pranking Fluttershy there; it was Pinkie who stopped her.I find it easy to imagine that Dash would have done things like this back in her school days...It's still mean, of course...

Although, now that I've read the whole comic, I would prefer for this to be somewhat of a alternate universe, where FiM will happen mostly unchanged. This way, the writer could change a few details (Dash and Fluttershy staying friends with some of the friends they make in this comic, for examle) without having to worry about the canon.It would also avoid foregone conclusions!

I assume you've read the whole comic, though? Then you propably know the prank doesn't do any long-term damage...